The main problems with conventional optical resonance cavities are their complexity, reliability, and instability. In addition, they are limited to the frequency they operate at and require high voltage to operate them. These devices are not easily built and much less reliable since they consist of a plethora of devices such as complex manufacturing steps, complex alignment fixtures and multiple parts requiring precision alignment. In addition, properly aligning the parts can be difficult and time-consuming, resulting in a complex, less reliable, and expensive resonance cavity. The assembly of such devices is lengthy and problematic requiring complicated alignment and holding fixtures for the mirrors. FIG. 1 is an example of the construction prevalent to date. FIGS. 1 and 2 show the complex structure, precision alignments and alignment tooling needed to achieve a cavity. In these respects, the simple resonance cavity according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing, provide an apparatus primarily developed for providing a cavity which can be tuned and is packaged in an environmentally rugged way. This simplification of design and packaging benefits results in a novel construction with the attributes herein listed and subsequently described. FIGS. 3 and 4 show an inherently much simpler structure that has multiple benefits including inherent temperature compensation, very high frequency operation (>150 kHz), low voltage operation (˜1.5 volt/FSR) at resonance mode and is environmentally rugged.